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Biomedical subjects

D P Jewell

Publications and source records attributed to D P Jewell.

At least 19 recordsLinked to original sources
PubMed1995

Increased expression of CD44v6 and CD44v3 in ulcerative colitis but not colonic Crohn's disease.

Immune mechanisms, possibly involving cell-surface molecules such as CD44, have been invoked to explain the pathogenesis of inflammatory bowel disease. We used monoclonal antibodies against epitopes encoded within the variable region of CD44 to investigate CD44 isoform expression in colon, small intestine, and liver in patients with various intestinal disorders and in controls. Biopsy samples from patients with ulcerative colitis showed significantly increased epithelial expression of CD44 isoforms containing the v6 and v3 epitopes, detected with antibodies 2F10 and 3G5, respectively. CD44v6 was detected on colonic crypt epithelial cells in 23 of 25 ulcerative colitis samples compared with 3 of 18 colonic Crohn's disease samples (p = 3.0 x 10(-6); odds ratio 57.5 [95% CI 6.83-702]) and 3 of 52 controls (22 normal colon, 10 infective colitis, 2 radiation colitis, and 18 colonic Crohn's disease; p < 1 x 10(-8); odds ratio 199 [25.5-2294]). No significant expression of CD44v6, CD44v3, or CD44v8/9 was found in samples of normal proximal colon from 4 patients with distal ulcerative colitis, whereas samples from the affected area showed staining for CD44v6 and CD44v3. No expression of CD44 variants was found in 15 samples of normal small intestine, 11 small-bowel pouchitis, 8 coeliac disease, 3 small-bowel Crohn's disease, 6 normal liver, 6 primary biliary cirrhosis, or 9 primary sclerosing cholangitis. The high intensity of CD44v6 and v3 epitope expression on crypt epithelial cells in ulcerative colitis suggests that CD44 isoforms may have an important role in ulcerative colitis. Their detection could have diagnostic potential in differentiating ulcerative colitis from other forms of colonic inflammation including Crohn's disease.

Antibodies, Monoclonal↗
PubMed1995

Site of action of platelet-activating factor within the mucosa of rabbit distal colon.

1. To determine how platelet-activating factor stimulates colonic anion secretion and increases epithelial permeability, epithelial sheets of rabbit distal colon excluding the submucosal neural plexus were mounted in Ussing chambers. The influence of specific inhibitors and 50 nmol/l platelet-activating factor on short-circuit current and transepithelial resistance was then investigated. 2. Pretreatment with 1 mumol/l indomethacin or 1 mumol/l doxantrazole abolished the biphasic stimulation of the short-circuit current and decrease in transepithelial resistance induced by platelet-activating factor. Addition of 10 mumol/l mepyramine attenuated the early phase and completely inhibited the late phase. Pretreatment with 1 mumol/l ranitidine, 0.1 mumol/l tetrodotoxin, 0.1 mumol/l ritanserin or a 5-lipoxygenase inhibitor (1 mumol/l MK886) had no effect. 3. To assess the influence of platelet-activating factor on epithelial function isolated from lamina propria elements, monolayers were cultured from a human colonic epithelial cell line (T-84). 4. The short-circuit current across monolayers mounted in Ussing chambers stimulated by 10 mumol/l ionomycin could be inhibited by pretreatment with ouabain or frusemide, consistent with the capacity for chloride secretion. Addition of platelet-activating factor (up to 500 nmol/l) had no effect on short-circuit current or transepithelial resistance. Receptor expression was examined with [3H] platelet-activating factor in isolated T-84 and HT-29 cells and found to be absent. 5. The influence of physiological concentrations of platelet-activating factor on colonic epithelial anion secretion and increased permeability in rabbit distal colon is indirect and consistent with mediation by prostaglandins released from mucosal mast cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Adhesion molecules intercellular adhesion molecule-1 (ICAM-1), ICAM-3 and B7 are not expressed by epithelium in normal or inflamed colon.

Adhesion molecules are involved in facilitating cell-mediated immune events. Because lymphocyte-epithelial cell interaction has been implicated in the pathogenesis of colonic inflammation, we analysed expression of a range of adhesion molecules on colonic epithelium in vitro and in vivo using flow cytometry, immunohistochemistry and in situ hybridization. Expression of ICAM-1 by cell lines HT29 and int407 was increased by proinflammatory cytokines interferon-gamma (IFN-gamma), tumour necrosis factor-alpha (TNF-alpha) and IL-1 but not by IL-6. Vascular cell adhesion molecule (VCAM) and E-selectin were not expressed. Immunohistochemistry using sections of inflamed colon from 16 patients with ulcerative colitis (UC), five patients with Crohn's disease (CD) and seven patients with normal colonoscopic biopsies, showed no expression of ICAM-1 on colonic epithelium. VCAM was seen in isolated lymphoid aggregates and E-selectin was expressed on endothelium. In situ hybridization showed no ICAM-1 or ICAM-3 mRNA in colonic epithelium. B7, the ligand for CD28, was not found on normal or inflamed colonic epithelium. The adhesion molecules ICAM-1, ICAM-3 and B7 are not involved in lymphocyte-epithelial cell interaction in the normal or inflamed colon. This may have implications for the development of T cell tolerance to intestinal luminal antigens.

Antigen-Presenting Cells↗
PubMed1995

Pelvic and perineal complications of Crohn's disease: assessment using magnetic resonance imaging.

This study evaluated the role of magnetic resonance imaging (MRI) in the demonstration of the pelvic and perianal complications of Crohn's disease. Twenty five patients with active Crohn's disease were studied (12 male; mean age 41.1 years). MRI examinations were performed using a 1.5 Tesla system, within 14 days after clinical assessment. T1 and T2 weighted fast spin echo sequences in two or three orthogonal planes were performed, with fat suppression in some cases. The MRI results were correlated with surgical and clinical findings. In 16 patients, cutaneous, deep perineal or enterovesical fistulas or abscesses were diagnosed at MRI which showed close correlation with findings at examination under anaesthetic. In eight patients no fistulas or abscesses were seen at MRI nor was there any evidence of complications on clinical examination and flexible sigmoidoscopy. There was one false negative examination in a patient who had a colovesical fistula. In conclusion, MRI can accurately show the pelvic and perineal complications of Crohn's disease and may render examination under anaesthetic unnecessary.

Abdominal Abscess↗
PubMed1995

HIV associated cytomegalovirus colitis as a mimic of inflammatory bowel disease.

Cytomegalovirus (CMV) colitis may cause symptoms and signs identical to those of idiopathic inflammatory bowel disease. Although difficult to diagnose with certainty, the histological finding of cytomegalovirus inclusions in tissue from a case of suspected inflammatory bowel disease is strongly suggestive. CMV colitis is an entity almost entirely confined to cases of severe immunosuppression. The case of a 79 year old widower who was admitted to hospital with symptoms suggestive of inflammatory bowel disease is presented. Despite medical treatment his condition worsened and he developed toxic dilatation of the colon requiring colectomy. Histological examination showed a mild superficial pancolitis, with focal severe inflammation, deep fissuring ulceration, and pseudopolyposis. Abundant CMV inclusions were seen in cells associated with the ulcerating inflammatory tissue. A diagnosis of indeterminate colitis with CMV was made. The patient's condition worsened after surgery and he died a few days later despite intensive treatment, including antiviral chemotherapy directed against CMV. After death HIV serology was found to be positive. Regardless of the age and perceived lifestyle of the patient, a diagnosis of CMV colitis in someone not known to be immunosuppressed raises the possibility of HIV infection.

Aged↗
PubMed1995

Are serum concentrations of nitric oxide metabolites useful for predicting the clinical outcome of severe ulcerative colitis?

OBJECTIVE: To determine serum concentrations of nitric oxide metabolites (NOX) in patients with severe ulcerative colitis and to assess whether these concentrations predict clinical outcome. PATIENTS: Twenty-six patients (16 men and 10 women, mean age 46 years) with severe ulcerative colitis requiring hospitalization for parenteral steroid therapy. Thirteen patients had a complete clinical response and symptoms resolved after 5 days of parenteral steroid administration; 13 made an incomplete recovery and needed further treatment (six cyclosporin, seven colectomy). METHODS: Serum concentrations of NOX and C-reactive protein (CRP) were measured daily for 3 days in all patients and as clinically indicated thereafter. The normal range for NOX was established by measuring the concentration in 25 healthy controls. RESULTS: Mean serum NOX and CRP concentrations were significantly elevated in both the patients with a complete and those with an incomplete response compared with controls (P < 0.001) on day 1 and fell during the first 3 days of therapy. On day 3, mean serum concentrations of NOX and CRP were lower in the patients with a complete response, but only the difference in CRP attained statistical significance (P = 0.02). There was no correlation between NOX and CRP concentrations. CONCLUSIONS: In the majority of patients with severe ulcerative colitis, circulating concentrations of NOX are increased at presentation and fall promptly during parenteral steroid therapy, irrespective of clinical outcome. However, in a small number of patients NOX concentrations do not fall during steroid treatment and such patients will probably require additional medical therapy or surgery.

Adult↗
PubMed1992

Phenotypic characterization of isolated intraepithelial lymphocytes in patients with ulcerative colitis and normal controls.

A method was developed to isolate colonic intraepithelial lymphocytes in patients with ulcerative colitis (N = 8) and normal controls (N = 13) in order to characterize their phenotype using a panel of monoclonal antibodies and flow cytometry. In both groups, the majority of the cells are of the CD3+CD8+ phenotype associated with cytotoxic/suppressor function. The CD4/CD8 ratios were similar. Virtually no B cells or macrophages were found. An increase in cells coexpressing the CD3 and HLA-DR molecules and a decrease in natural killer cells (CD3, CD16+CD56+) were found in ulcerative colitis, but this was not significant. There were no differences in the proportions of CD8+ and CD4+ cells expressing the Leu8 antigen between ulcerative colitis and controls. Thus a population of colonic intraepithelial lymphocytes has been isolated and, although they may be functionally different in ulcerative colitis compared with controls, this cannot be explained in terms of phenotypic characteristics.

Adult↗
PubMed1992

Regional differences in the response to platelet-activating factor in rabbit colon.

1. Platelet-activating factor is an inflammatory mediator related to eicosanoids which is known to stimulate anion secretion in the distal colon. Since there are regional differences in ion transport within the colon, the influence of platelet-activating factors on ion transport and epithelial permeability has been studied in rabbit caecum and distal colon mounted in Ussing chambers. 2. The effect of platelet-activating factor (1-50 nmol/l) on net electrogenic ion transport was to stimulate a biphasic increase in short-circuit current in the distal colon but not in the caecum. The platelet-activating factor-induced rise in short-circuit current was shown by ion replacement and pharmacological inhibitor studies to be consistent with chloride and bicarbonate secretion in the early phase, but with chloride secretion alone in the later phase. The effect on ion transport was specific and reversible and was enhanced by 0.25% BSA. 3. Colonic permeability, assessed by transmucosal resistance and mannitol flux, was increased by platelet-activating factor in both the distal colon and the caecum. This was consistent with an effect on platelet-activating factor on the paracellular pathway, because resistance decreased even when transcellular chloride transport was inhibited by frusemide or ion replacement. A specific platelet-activating factor antagonist (U66985) inhibited the effects of platelet-activating factor in both the distal colon and the caecum. 4. The results show that platelet-activating factor stimulates anion secretion only in the distal colon, but increases permeability in both the caecum and the distal colon.

Animals↗
PubMed1992

Production of epithelial cell growth factors by lamina propria mononuclear cells.

The effects of lamina propria mononuclear cell culture supernatant on epithelial cell DNA synthesis were studied using cells isolated from patients with inflammatory bowel disease and normal controls. Supernatants from resting and phytohaemagglutinin stimulated cells were studied and supernatants that strongly promoted DNA synthesis were pooled, and growth factor activity partially characterised. The effects of recombinant interleukins-1 beta,2,3,interferon-gamma, and granulocyte macrophage colony stimulating factor were tested in the same system. Resting lamina propria mononuclear cells produce factors that increase DNA synthesis. Production of these factors is increased by phytohaemagglutinin stimulation. No significant differences were found in production of these factors between patients with inflammatory bowel disease and normal controls. The molecular weight of the active factor(s) lies in the region 31-48 kD. Chromatofocusing produced two peaks of activity, one in the region pk 5.5 and one around pk 6.4. The activity was heat and acid pH labile. Activity was not destroyed, however, by 0.05% trypsin. Recombinant granulocyte macrophage colony stimulating factor was a weak stimulus to epithelial DNA synthesis, interleukin-1 beta was weakly inhibitory but other cytokines tested did not have any effect. Granulocyte macrophage colony stimulating factor is probably important in controlling epithelial cell growth.

Aged↗
PubMed1992

Salicylates used in inflammatory bowel disease and colchicine impair interferon-gamma induced HLA-DR expression.

Colonic epithelial cells express HLA-DR in inflammatory bowel disease. The effect of drugs used in the treatment of inflammatory bowel disease and colchicine on interferon-gamma (IFN-gamma) induced DR expression has been investigated. HT-29 cells were cultured in 25 cm2 flasks. At 48 hours interferon-gamma (0, 50, or 100 U/ml) +/- drug were added. At 120 hours the cells were stained for HLA-DR and analysed by flow cytometry. 10(-2) M 5ASA reduced DR expression induced by 50 U/ml interferon-gamma from 62 (12)% of cells (mean SD) to 29 (20)% (p less than 0.005). Corresponding figures for 10(-2) M N-acetyl 5ASA were 68 (16)% to 39 (17)% (p less than 0.05); for 10(-2) M 4ASA, 61 (4)% to 57 (4)% (p = 0.6); for 10(-2) M N-acetyl 4ASA, 60 (12)% to 35 (13)% (p less than 0.05); for 10(-2) M olsalazine, 72 (9)% to 3 (1)% (p less than 0.001); for 10(-3) M olsalazine, 72 (9)% to 16 (10)% (p less than 0.001); for 10(-6) M colchicine, 62 (13)% to 5 (3)% (p less than 0.001); and for 10(-7) M colchicine, 62 (13)% to 10 (3)%. Similar results were obtained when DR was induced by 100 U/ml of interferon-gamma except with 10(-2) M 4ASA which reduced expression from 77 (4)% to 68 (3)% (p less than 0.05). Sulphapyridine, prednisolone, indomethacin and cyclosporin A had no effect. Concurrent staining with propidium iodide showed that these results were unchanged when viable cells alone were analysed. Prior incubation of cells with drug, followed by washing, had no effect on interferon-gamma induced DR expression. 5ASA, N-acetyl 5ASA, 4ASA, N-acetyl 4ASA, olsalazine and colchicine reduce interferon-gamma induced HLA-DR expression. In inflammatory bowel disease these compounds may impair antigen presentation by the colonic epithelium.

Aminosalicylic Acid↗
PubMed1992

Changing pattern of gastric cancer in Oxfordshire.

This study compares the incidence rates of histologically confirmed gastric carcinoma in Oxfordshire in two five year periods (1960-64, 1984-88). Data were available for 215 patients in the first period, and 200 in the second. The overall incidence fell from 18/100,000 to 15/100,000 but when analysed for site, the incidence of antral tumours fell from 10 to 4.5/100,000. In contrast, there was an increase from 2.8 to 5.2/100,000 of tumours of the cardia. These changes were more pronounced in men. There was a marked association between smoking and tumours of the cardia (relative risk 4.5). Helicobacter pylori was associated with 37.5% of tumours in the 1960s series compared with 25% in the later series. The changing patterns of incidence of gastric carcinoma may, in part, be related to changes in smoking habits and perhaps a change in incidence of H pylori infection.

Age Factors↗
PubMed1992

Comparison of 5-aminosalicylic acid and N-acetylaminosalicylic acid uptake by the isolated human colonic epithelial cell.

Isolated human colonic epithelial cell suspensions were incubated with either 0.1 mM 5-aminosalicylic acid (5-ASA) or 0.1 mM acetylaminosalicylic acid (Ac-ASA) for up to two hours. Intra- and extracellular 5-ASA and Ac-ASA were measured by high performance liquid chromatography. Mean 5-ASA uptake in one hour was 160.5 nmol/g dry weight, compared with an Ac-ASA uptake of only 5.75 nmol/g dry weight. No unchanged 5-ASA was detected inside the cell. Repeated washing had no effect on the intracellular Ac-ASA concentration. This discrepancy in drug uptake may explain why Ac-ASA seems to be ineffective when given to patients with ulcerative colitis.

Aminosalicylic Acids↗
PubMed1992

Inhibition of binding of interferon-gamma to its receptor by salicylates used in inflammatory bowel disease.

5-Aminosalicylic acid (5ASA), 4ASA, their N-acetylated metabolites N-acetyl-5ASA and N-acetyl-4ASA, olsalazine, and colchicine impair interferon-gamma (IFN gamma) induced HLA-DR expression on a colonic cell line, HT-29. The mechanism of this effect is now reported. HT-29 cells were cultured with 50 U/ml IFN gamma with or without drug, and northern blot analysis was performed using a probe for the beta chain of the DR molecule. IFN gamma led to a noticeable increase in HLA-DR mRNA which was attenuated by the drugs. Analysis of the specific binding of increasing concentrations of 125I-IFN gamma by non-linear regression showed a Kd of 1.35 x 10(-10) M and 2.3 x 10(5) binding sites per HT-29 cell. Binding of 125I-IFN gamma was reduced by incubation with increasing concentrations of unlabelled IFN gamma but not with IFN alpha. Incubation with therapeutic concentrations of drugs led to the following reductions in binding: 10 mM 5ASA, 20% (p < 0.001); 10 mM N-acetyl-5ASA, 24% (p < 0.01); 10 mM 4ASA, 21% (p < 0.005); 10 mM N-acetyl-4ASA, 29% (p < 0.001); and 1 mM olsalazine, 29% (p < 0.001). Colchicine (10(-7) M) and 10(-5) M prednisolone had no effect. Incubation with higher concentrations of the drugs revealed a dose-response effect on binding with complete inhibition by 100 mM 4ASA and 10 mM olsalazine, and lesser degrees of inhibition by 100 mM 5ASA, N-acetyl-5ASA, and N-acetyl-4ASA. At concentrations found in the rectal lumen, the salicylates used in inflammatory bowel disease impair the binding of IFN gamma to its receptor on colonic epithelial cells.

Aminosalicylic Acid↗
PubMed1992

Characterisation and quantification of mucosal cytokine that induces epithelial histocompatibility locus antigen-DR expression in inflammatory bowel disease.

Epithelial histocompatibility locus antigen (HLA) class II expression was studied to evaluate its induction by mucosal mononuclear cells in inflammatory bowel disease and to characterise the responsible cytokine. Unstimulated cells of the HT-29 epithelial cell line did not produce class II molecules. After being stimulated with the mitogenic lectin phytohaemagglutinin mucosal mononuclear cells released a cytokine that induced epithelial HLA-DR expression. The cytokine had the physicochemical and immunological characteristics of interferon-gamma, and no additional cytokines were detected.

Adolescent↗
PubMed1992

Antigen induced suppression in peripheral blood and lamina propria mononuclear cells in inflammatory bowel disease.

Using an autologous system, suppressor cell function to a range of mycobacterial antigens and Kunin antigen of peripheral blood mononuclear cells and lamina propria lymphocytes has been investigated in normal subjects and patients with inflammatory bowel disease. In the peripheral blood there was reduced antigen induced suppression in patients with Crohn's disease in remission to Mycobacterium paratuberculosis, purified protein derivative (PPD), M fortuitum, and Kunin antigens (p less than 0.05). In patients with ulcerative colitis in remission there was reduced antigen induced suppression in the peripheral blood to Kunin antigen (p less than 0.001), M avium (p less than 0.01), M nonchromogenecin, and M fortuitum (p less than 0.05). The phenomenon of antigen induced suppression was largely CD8 dependent, as depleting CD8+ cells reduced the effect and the concentration of soluble CD8 in the culture supernatant was directly related to the suppressor index (r = 0.25, p less than 0.05). These results are likely to be a true reflection of the cell mediated response to antigen as patients with a positive Mantoux skin test have a significantly higher suppressor index to PPD than Mantoux negative subjects (p less than 0.05). These findings may have significance in the aetiopathogenesis of inflammatory bowel disease. However, a similar effect could not be shown in the lamina propria lymphocytes of patients having colectomy for active disease.

Adult↗
PubMed1992

Oral fluticasone propionate in active distal ulcerative colitis.

Fluticasone propionate is a new corticosteroid with low systemic bioavailability. This study reports the outcome of a double blind clinical trial comparing oral fluticasone propionate (5 mg four times daily) with placebo for the treatment of active distal ulcerative colitis. Sixty patients were treated for four weeks, with assessments at two and four weeks. One patient was withdrawn when she was found to have amoebiasis. Thus, results are presented for 29 patients who received placebo and 30 who received fluticasone propionate. The two groups were well matched for age, sex, length of history, and extent of disease. After four weeks of therapy the clinical, sigmoidoscopic, and histological responses were similar in the two groups. It is concluded that fluticasone propionate (5 mg four times daily) is not effective treatment for active distal ulcerative colitis.

Administration, Oral↗